Answer:
Simple answer: I think WW| would not have occured if the archduke wasn't assassinated.
Without the assassination of Archduke Franz Ferdinand, there would have been no need for rulers in Vienna to threaten Serbia, no need for Russia to come to Serbia's defense, no need for Germany to come to Austria's defense — and no call for France and Britain to honor their treaties with Russia.
Step-by-step explanation:
Theory: Without World War I, there is no World War II and no Cold War. Science develops much slower — the U.S. doesn't put a man on the moon, there is no atomic bomb, and penicillin and antibiotics are slower to hit the market.
I hope this helps you in any shape or form.